"Our sensor measures the oxygen content in people’s breath, which allows us to extrapolate to the blood oxygen concentration," says Mahmoud El-Safoury, project manager at Fraunhofer IPM.
The novel sensor is based on the principle of fluorescence quenching. A fluorescent layer is illuminated with light and emits light with a longer wavelength. When oxygen comes into contact with the layer, the emitted light is attenuated. The intensity of the attenuated light allows conclusions to be drawn about the oxygen concentration in the respiratory gas and therefore in the blood.
"Quenching is already used to determine the concentration of dissolved oxygen in liquids in sectors such as the food industry and at water and wastewater treatment plants, for example. It’s a novel method in medical engineering, though," says Dr. Benedikt Bierer, group manager at Fraunhofer IPM.